Soak the Rice and Lentils: In one large bowl, combine the idli rice and fenugreek seeds. Rinse them thoroughly under cold running water until the water runs clear. In another separate bowl, rinse the urad dal until the water is clear. Cover both the rice and dal with plenty of fresh, filtered water and let them soak for 8-10 hours, or overnight. You’ll notice the grains will swell significantly, looking plumper and softer.

Grind the Dal: Drain the soaked urad dal completely. Transfer the dal to your wet grinder or powerful blender. Add about 100-150ml of chilled water, a little at a time, to help with grinding. Grind until you achieve a very smooth, light, and fluffy batter. It should be thick and aerated, almost like whipped cream, and will have a pale, off-white colour. This process might take 20-30 minutes in a wet grinder, or about 5-7 minutes in a high-speed blender, stopping to scrape down the sides.

Grind the Rice: Drain the soaked rice and fenugreek seeds. Add them to the same grinder (no need to wash it out) with about 150-200ml of chilled water. Grind until the rice batter is relatively smooth, but still has a slightly coarse, grainy texture – think fine semolina. This gives idlis their characteristic structure. It should be a creamy white colour.

Combine and Ferment the Batter: Transfer both the ground dal and rice batters to one very large mixing bowl. Add the salt. Using your clean hand, gently mix the batters together. Mixing with your hand helps incorporate air and introduces beneficial microbes, which aids fermentation. Mix for about 2-3 minutes until well combined. The mixture should feel smooth and slightly gritty. Cover the bowl loosely with a lid or clean cloth, allowing air to circulate. Place the bowl in a warm spot in your kitchen (ideally around 25-30°C or 77-86°F) to ferment for 8-12 hours, or until the batter has doubled in volume and a pleasant, slightly sour aroma develops. You'll see tiny bubbles on the surface, indicating active fermentation.

Prepare for Steaming: Once fermented, gently stir the batter with a ladle. Do not overmix, as this will deflate the air bubbles. The batter should be thick, airy, and flow like a rich cream. Lightly grease your idli moulds with a little oil or ghee. Heat water in your idli steamer or pressure cooker (without the whistle) until it’s simmering steadily.

Steam the Idlis: Pour the idli batter into each mould, filling them about three-quarters full. Carefully place the idli stand into the preheated steamer. Close the lid and steam for 10-15 minutes over medium-high heat. You'll hear the water bubbling and steaming vigorously. To check for doneness, gently open the lid – the idlis should look puffed up and glossy white. Insert a skewer or toothpick into the centre of an idli; it should come out clean.

Rest and Serve: Once cooked, turn off the heat and let the idlis rest in the steamer for 2-3 minutes. This allows them to firm up slightly. Carefully remove the idli stand. Using a wet spoon or knife, gently scoop out each idli from its mould. They should release easily, appearing beautifully round, soft, and warm to the touch. Serve immediately.